print(1 + 2 - 3)
print(1 + 2 * 3)
print(1 + 2 / 3)

a = 10
print(type(a))

a = 0.5
print(type(a))

a = 'hello'
print(type(a))

a = 'hello'
b = 'world'
print(a + b)

a = True
print(type(a))
b = False
print(type(b))

a = 10
print(type(a))
a = 'hello'
print(type(a))

# 计算 4 个数字 67.5, 89.0, 12.9, 32.2 的方差
avg = (67.5 + 89.0 + 12.9 + 32.2) / 4
total = (67.5-avg) ** 2 + (89.0-avg) ** 2 + (12.9 - avg) ** 2 + (32.2 - avg) ** 2

result = total / 3
print(result)